Method of flanging can bodies



Nov. 24, 1942.

C. S. BURDORF METHOID FOR FLANGING CAN BODIES Filed March 22, 1940 f/vns/vrok I Patented Nov. 24, 1942' METHOD OF FLANGING CAN BODIES Carl S. Burdori, Cincinnati, Ohio, assignor to Continental Can Company, Inc., New York, N. Y., a corporation of New York Application March 22, 1940, Serial No. 325,442

1 Claim.

The invention relates to new and useful improvements in a method of flanging can bodies and particularly can bodies to which end closures are to be double-seamed.

One of the usual methods of flanging can I bodies consists in subjecting the formedcan body the curvature is on a larger radius, and this interferes with the tucking of the flange of the closure end well up under the flange of the body during the forming of the double seam. The

double seam, therefore, where it crosses the side seam is less tight than other portions of the side seam, and this often results in a leaky joint.

An object of the present invention is to provide a method of forming a flange on a can body preparatory to double-seaming an end thereto, wherein the flange shall be .of the same radius at the side seam as at other portions of the body. a

A further object of the invention is to provide a method of weakening, without rupturing, the outer lap section of the side seam along a line substantially parallel with the end edge of the can body and at a, distance from the edge substantially equal to the depth of the flange to be formed prior to the die-shaping of the body to produce a flange to which the end closure is to be joined by double-seaming.

A still further object of the invention is to provide a method of the above type wherein the weakening of the outer lap section of the side seam is accomplished by a bumping action at the same time that the side seam is bumped prepara- Figure 4 is a sectional View taken at the side seam after flanging.

Figure 5 is a sectional view of a can body at one side of the side seam after flanging. 1 The invention relates broadly to a method of producing a, flanged can body from sheet metal. A sheet metal blank is formed with hooks and lapping portions to be joined into a side seam. The body is then shaped so that the hooks engage and the hooks are bumped forlthe purpose of locking the side seam. The bumping iron is of the usual construction except for the provision of projecting ribs which are disposed so as to contactthe body of the can during the bumping operation of the hooked portion. These ribs en gage the lapped sections of the seam about midway between the outer edge and the inner edge of the lapped sections and simultaneously with thebumping of the hooks form a groove or weakened line in the lapped portions parallel to the edge of the can. This groove is so disposed that during flanging it lies right at the angle of the flange and at a distance from the edge of the body blank substantially equal to the depth of the flange to be formed. This enables the metal to turn more easily in the region of the side seam when the can body is subjected to a flanging die for rolling the edge portion outwardly into a flange, and a flange of substantially uniform radius throughout the entire extent thereof will be formed.

Referring more in detail to the drawing, a method of producing a flanged can body according to the invention is more or less diagrammatically shown. Referring to Figure 1, a can body 6 is shown having a lapped portion I and a hooked portion 8 which are to be joined into a side seam. This figure of the drawing is intended to illustrate a can body which is made of sheet metal, and provided with interengaging hooked portions and overlying lapped portions prior to bumping the hooked portions to form the side seam.

Figure 2 of the drawing shows the can body after the bumping operation has been performed, and a groove 9 is shown which is indented in the lapped portions of the seam simultaneously with the bumping of the hooked portions of the seam. This groove is formed by providing projecting ridges in a bumping iron (not shown) which is of usual construction except for the ridges which form the groove. The ridges in the iron are so disposed as to engage the lapped sections of the side seam about midway between the outer edge as indicated at l 0 and the inner edge as indicated at l I of the lapped sections '1 and form the groove 9 parallel to the upper edge I!) of the body blank 6 which extends substantially the full width of the lapped sections 1.

In Figure 3 the depth of the groove is indicated, from which it will be seen that the groove merely weakens the structure of the metal in the region of the side seam and does not rupture the same. After the hooked parts are bumped and the groove at the same time is formed, the lapped sections may be solder-bonded together if so desired.

Figure 4 of the drawing shows the can body after it has been subjected to a flanging die for rolling the edge portion thereof outwardly into a flange I2. The groove 9 is so disposed that during flanging'it lies right at the angle of the flange and at a distance from the edge of the body blank substantially equal to the depth of the flange to be formed.

By providing such a groove 9 as described above, the metal in the region of the side seam where there are two thicknesses solder-bonded together will turn with substantially the same ease as the metal of other parts of the flange (Figure 5), and a flange of substantially uniform radius throughout its entire extent will be formed. Thus, when an end is seamed to the container, a doubleseam of uniform tightness may be formed. This groove also helps to make a rounder can. When the metal at the cap is weakened by grooving the same as above described, the tendency to pull the side seam out at this point when flanging is lessened. Furthermore, the groove lessens the rupturing of the solder bonds at the lap portion during the flanging operation by taking a certain amount of strain off from the solder.

While in the drawing a lock and lap type of can body is shown, it may be easily understood that the groove provided by the applicant as a part of his invention might be applied to a can body having a lapped side seam. only for facilitating in flanging the ends thereof. It may be also understood that while a longitudinal groove is provided in this form of the invention for weakening the structure of the metal in the region of the side seam, several indentations, scoring or beading of the metal might be utilized without departing from the spirit of the invention as set forth in the appended claim.

I claim:

The method of flanging sheet metal can bodies having solder bonded lock and lap side seams,

consisting in bumping the side seam and simultaneously therewith inwardly indenting on a small curve the lap sections of the side seam. on a line parallel to the edge of the body and midway between the outer and inner ends of the lap portion, said indentation extending only across the lap sections of the side seam, applying solder to the side seam for solder bonding the same and finally subjecting the body at the end thereof containing the indented lap portions to a flangin die shaped so as to expand the edge portion of the can body and the said indentation outwardly to form a flange of relatively large curvature which merges with the wall of the can body on a relatively large curve extending throughout a greater portion of the length of the lap sections, said indented portion being relatively small compared with the curved portion and disposed between the ends of the curved portion so that the metal in the lap sections is shaped by the flanging die on a curve of substantially the same radius as merging into said large curve.

CARL s. BURDORF. 

